HESI A2 Physics

Correct Answer: D

Rationale: To calculate impulse, we use the formula Impulse = Change in Momentum. First, calculate the initial momentum: initial momentum = 10 kg * 5 m/s = 50 kg⋅m/s. Then, calculate the final momentum: final momentum = 10 kg * 15 m/s = 150 kg⋅m/s. The change in momentum is final momentum - initial momentum = 150 kg⋅m/s - 50 kg⋅m/s = 100 kg⋅m/s. Therefore, the impulse applied to the object is 100 kg⋅m/s. Choice D is correct as it correctly represents the impulse value. Choices A, B, and C are incorrect as they do not accurately reflect the calculated impulse value.

Correct Answer: C

Rationale: The correct answer is C: Heat. When current flows through a circuit with resistance, the resistance causes collisions between electrons and atoms, resulting in energy loss in the form of heat. This is known as Joule heating. Light (A) is not typically generated by electrical resistance, and sound (B) is not a common form of energy dissipation in circuits. Mechanical work (D) involves movement and is not directly related to energy dissipation due to resistance.

Correct Answer: D

Rationale: The momentum of an object is calculated by multiplying its mass by its velocity. In this case, the glider has the greatest momentum because it has the highest product of mass and velocity compared to the other choices. The glider's momentum is calculated as 500 kg * 89 m/s = 44500 kg*m/s, which is higher than the momentum of any other vehicle listed. The other choices have lower momentum values due to either lower mass, lower velocity, or both. So, the correct answer is D because it has the greatest momentum based on its mass and velocity.

Correct Answer: B

Rationale: To calculate the current flowing through the circuit, we use Ohm's Law: I = V / R. In this case, the total resistance in series is 5 + 5 = 10 ohms. So, I = 100 V / 10 ohms = 10 A. Therefore, choice B (10 A) is correct. Choices A (2 A), C (20 A), and D (50 A) are incorrect because they do not correctly calculate the current based on the total resistance of the circuit. Choice A underestimates the current, choices C and D overestimate it, while only choice B provides the accurate calculation based on Ohm's Law.

Correct Answer: B

Rationale: To determine the stretch of the spring when a 30 kg force is applied, we first calculate the spring constant using Hooke's Law: F = kx. Given F1 = 12 kg and x1 = 3 cm, k = F1/x1 = 12 kg / 0.03 m = 400 N/m. Then, for F2 = 30 kg, x2 = F2 / k = 30 kg / 400 N/m = 0.075 m = 7.5 cm. Therefore, choice B (7.5 cm) is the correct answer. Choices A, C, and D are incorrect as they do not align with the calculated value using Hooke's Law.